It appears that the shot to the thumb was a grazing one, and could account for one "entry" to the forearm (or the upper arm). The grazing shot at the elbow was likely a "lost" round (not collected, and not counted as a hit). I'm not sure what the examiner intended by the three wounds to the right side of his face and neck, but the chin-shot indicates another grazing wound, ending near his right medial clavicle. That there are no exit wounds suggest an inferior police cartridge.
That would account for the 3 wounds on the right side of Brown's face.